This invention relates generally to the field of hypodermic syringes, and more particularly to an improved barrel shield for protecting technicians administering radioactive materials to patients on a daily basis. Shields of this general type are known in the art, and the invention lies in specific constructional details which offer a number of advantages not available with conventional shielding construction.
The typical prior art shield construction widely used at the present time comprises a relatively heavy sleeve or barrel of lead or titanium having a central, longitudinal bore which accommodates the barrel of the syringe. A set screw or resilient means, or combination of the two is provided to lock the syringe within the shield, and, in the case of improved types, there is included a means for partially retracting the shield to permit dosage calibration prior to administering the contents of the syringe to the patient.
However, all of the prior art devices exhibit in varying degrees one or more of several disadvantages.
Because of the weight of the materials from which the shields are made, the prior art devices tend to be very heavy, and are bulky as well. In addition, since the shielding material is used for structural rigidity as well, considerable machining operations are necessary during fabrication, resulting in very high production costs, and consequent limited sale and distribution. Further, with use, the syringe tends to loosen within the shield, calling for periodic adjustment of the locking means.
Another difficulty lies in the fact that in many cases the shield must be removed for radioactivity dosage calibration. In the case of any retractable type, this step is unnecessary. Also, sufficient visibility is not afforded when the needle of the syringe is in the vein of the patient.